Merge branch 'tcp-avoid-sending-too-small-packets'

Eric Dumazet says:

====================
tcp: avoid sending too small packets

tcp_sendmsg() cooks 'large' skbs, that are later split
if needed from tcp_write_xmit().

After a split, the leftover skb size is smaller than the optimal
size, and this causes a performance drop.

In this series, tcp_grow_skb() helper is added to shift
payload from the second skb in the write queue to the first
skb to always send optimal sized skbs.

This increases TSO efficiency, and decreases number of ACK
packets.
====================

Link: https://lore.kernel.org/r/20240418214600.1291486-1-edumazet@google.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>